Hsp70 (heat shock 70 kDa) chaperone proteins are central to protein folding, refolding, and trafficking in organisms ranging from Archae to Homo Sapiens, both at normal and at stressed cellular conditions. Hsp70's (re) fold proteins via binding and release cycles at the substrate-binding domain involving conformational changes caused by ATP and ADP binding at the nucleotide-binding domain. This remote regulation mechanism is called allostery. Recently, Hsp70's have been linked to diseases such as breast cancer. Modulation of the allosteric mechanism of the Hsp70's with small compounds may form an avenue to treat these diseases. We propose to investigate the mechanism in detail by determining the solution conformations of 60 kDa Hsp70 protein constructs, containing both nucleotide- and substrate-binding domains and their complexes with co-chaperones in different liganded states. We will investigate the molecular basis for the action of the first generation of Hsp70 modulating compounds. The combined insights gained will aid in the design of improved compounds for the treatment of cell-management diseases. The research will be carried out using ultra-high field nuclear magnetic resonance spectroscopy.